Journal of Nanoparticle Research最新文献

This study employs spin-polarized density functional theory (DFT) to explore the structural and electronic properties of ZnO-decorated single-walled carbon nanotubes (ZnO-SWCNT) before and after SO₂ and SO₂F₂ adsorption. In ZnO-SWCNT, the ZnO molecule shifts to the hollow part of the CNT after relaxation, and the nanotube’s band gap is about 0.37 eV. However, SO₂ chemisorption could convert the electronic property to metallic. The SO₂ molecules adsorb to the Zn atom of the modified nanotube with a high adsorption energy of − 0.93 eV and 0.23 electron transfer from the nanotube to SO₂. SO₂F₂ adsorption energy to ZnO-SWCNT is about − 0.7 eV. This adsorption slightly increases the band gap and does not lead to a considerable charge transfer which can be interpreted as physical adsorption of SO₂F₂ to SWCNT. These computational insights provide an accurate understanding of the structural and electronic properties of ZnO-SWCNT which can potentially guide the rational design of ZnO-SWCNT as a sensor for adsorption of SF₆ decomposed gases.

A series of Ag-TiO₂ nanotube catalysts were prepared by electrochemical deposition. Doping of Ag nanoparticles was regulated by adjusting the deposition voltage, which altered the photocatalytic performance of the sample. The electrochemical properties of the Ag-TiO₂ nanotubes were characterized using X-ray photoelectron spectroscopy, scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy, and ultraviolet–visible (UV–vis) diffuse reflection spectroscopy. PL and UV–vis spectroscopy showed that the Ag-TiO₂ nanotubes had a higher visible-light absorption activity and a lower photogenerated electron–hole pair recombination rate. SEM analysis showed that the highly ordered tubular structure of the TiO₂ nanotubes was not disrupted after electrochemical deposition, and the size and quantity of the Ag nanoparticles deposited on the TiO₂ nanotubes increased with increasing deposition voltage. The Ag-TiO₂ nanotubes prepared at a deposition voltage of 1 V exhibited the highest hydrogen evolution efficiency, with a theoretical hydrogen production rate of 12.59 µmol∙cm⁻²∙h⁻¹ under UV irradiation. This was 2.1-fold higher than that of pure TiO₂ nanotubes and was attributable to the local surface plasmon resonance effect of Ag nanoparticles, which enhanced the visible light absorption by the TiO₂ nanotubes.

The development of activatable nanoplatforms to enhance diagnostic and therapeutic performance while minimizing side effects is of great significance in treatment of chronic hepatitis B (CHB). Here, we report a novel nanomaterial composed of graphitic carbon nitride (g-C₃N₄) and 5-aminolevulinic acid (5-ALA), onto which our newly synthesized compound 1 is loaded, forming 5-ALA/g-C₃N₄@1. This nanomaterial is highly pH-sensitive and can rapidly degrade in mildly acidic environments, enabling the release of its loaded photosensitizer and compound 1, exhibiting characteristics such as fluorescence recovery and increased singlet oxygen generation. We evaluated the bioactivity of this novel composite material and explored its mechanisms of action. The effect of 5-ALA/g-C₃N₄@1 on the levels of HBV DNA, HBsAg and HBeAg was evaluated by treatment of HepG2.2.15 cells with the system. Our results suggest that the system can effectively inhibit HBV replication for the treatment of CHB. This work presents a novel photosensitive carrier with excellent biocompatibility and therapeutic efficacy, offering new insights into CHB research.

Borophene, as a 2D rising eulogizing star, is garnering increasing attention and recognition due to its venerated properties including anisotropic plasmonics, exemplary in-plane elasticity, superconductivity, massless Dirac fermions, high electron mobility, exceptional flexibility, exquisite tunability, and metallic properties across the majority of its structural models. These characteristics make borophene a promising material with diverse implementations like quantum electronics, high-speed low-dissipation devices, gas sensors, and energy storage. Following the landmark synthesis of borophene in 2015, a multitude of scientific endeavors have explored diverse synthesis approaches for producing borophene on a range of substrates. Within, this comprehensive review, we endeavor to present a succinct yet thorough examination of the myriad synthesis approaches employed for borophene fabrication on various substrates. In tandem, we meticulously delineate the merits and demerits inherent to each of these elucidated synthesis techniques. Furthermore, the review encompasses a summary of applications of borophene. Simultaneously, we proffer suggestions, address existing challenges, and discern novel prospects, thus extending an invitation for future exploration in this promising domain of scientific inquiry.

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In this study, a computational analysis based on density functional theory is conducted to study the elastic, mechanical, vibrational, and thermodynamic properties of novel chalcogens, Ag₂BeSnX₄ (X = S, Se, and Te). We used the generalized gradient approximation (GGA) within the framework of density functional theory (DFT). The mesh parameter values (a and c) were calculated using the X-ray diffraction method. The calculated elastic constants indicate that the bond strength along the [1 0 0] directions is stronger than that along the direction [0 0 1]; according to the Born-Huang stability criterion, we can see that they are mechanically stable. A high value of the ratio (B/G) is associated with ductility for Ag₂BeSnX₄ (X = S, Se, and Te) materials. Additionally, the Raman shifts of all samples are calculated. Between 10 and 1000 K in temperature, the vibrational mode shifts were calculated for three chalcoginides. The thermal behavior of these movements shows that these structures can undergo deformation with increasing temperature. These results suggest a first contribution to the understanding of the effect of temperature on the vibrational modes of three kesterite structures Ag₂BeSnX₄ (X = S, Se, and Te) and consequently on their structures. The heat capacity (({C}_{V})), free energy ((F)), entropy ((S)), and enthalpy ((H)) are also computed. The kesterite phase of the Ag₂BeSnX₄ (X = S, Se, and Te) structures aligns with theoretical findings in elastic properties, exhibiting superior elastic properties. These attributes are valuable for the design of optoelectronic devices.

Nano-priming is an emerging application of nanotechnology in agriculture intending to increase crop yield and nutritional quality while reducing fertilizer applications. This study aimed to investigate the effects of seed priming with citrate-coated CoFe₂O₄ nanoparticles (NPs) suspensions (10, 20, and 40 mg NPs L⁻¹) on the life cycle of the Phaseolus vulgaris L. OTI cultivar and evaluate the technology costs. The effect of nano-priming was assessed in the germination, flowering, and harvest stages. Unprimed and hydro-primed seeds were negative and positive controls, respectively. Nano-priming with CoFe₂O₄ NPs had no effect neither on the germination nor on plant nutrition (in the flowering stage) of OTI beans compared to unprimed and hydro-primed seeds. In contrast, nitrogenase activity (343.3 ± 1.1 µmol h⁻¹ plant⁻¹ of C₂H₄) was detected in the plants from the 40 mg kg⁻¹ nano-primed seeds. The K concentration of progeny seeds from nano-priming with 10, 20, and 40 mg NPs L⁻¹ increased significantly by 3%, 16%, and 13% compared to the control seeds. The Zn concentration in the seeds from nano-priming with 10 mg NPs L⁻¹ was 27% higher than in the control and 28% higher than in the hydro-primed seeds. When nano-priming with 40 mg NPs L⁻¹, the Zn concentration was 5% and 6% higher than the control and hydro-primed seeds. The calculated cost of nano-priming seeds per ha ranged from 121 to 143 USD. In this regard, nano-priming of bean seeds with citrate-coated CoFe₂O₄ NPs could be a low-cost approach to achieve nutritional security and agricultural sustainability.

Ultra-small iron oxide nanoparticles (USNPs) have attracted particular attention in the past 15 years as perspective contrast agents for MRI. Unfortunately, the synthesis of such small nanoparticles with high contrast properties and water dispersibility is still challenging. This paper presents a study on the influence of synthetic conditions on the structure and the properties of hydrophilic iron oxide nanoparticles obtained by a simple single-step thermal decomposition in diethylene glycol at 230–235 °C. The samples were studied using X-ray diffraction, Mössbauer and infra-red spectroscopy, transmission electron microscopy, vibrating sample magnetometry, MRI, and dynamic light scattering. All the obtained samples are of spinel structure (Fd-3 m), specific to both magnetite and maghemite. With an increase in the synthesis time from 1 to 8 h, the crystallite size of the series with C(Fe(acac)₃) = 30 mM changed from 1.8 ± 0.2 to 4.7 ± 0.5 nm, the average size according to TEM changed from 3.3 ± 0.8 to 3.8 ± 0.4 nm, and the saturation magnetization from 13.9 ± 0.3 to 83.3 ± 1.7 A•m²/kg, which is close to the values of bulk iron oxide. The same tendency was revealed with the increase in the concentration of C(Fe(acac)₃) from 30 to 120 mM for 1 h of synthesis. An increase in the synthesis time for 60- and 120-mM solutions did not significantly change the crystallite size and the magnetic properties. It was shown that the samples obtained using this approach have unexpectedly high values of r₂-relaxivity, up to 235 mM⁻¹•s⁻¹, which the highest published for USNPs. The studied method of water-soluble USNPs is promising for use in creating T₂-contrast agents for MRI.

Some physical properties of M-doped (M = Ag, Au) single-walled (6,0) silicon-carbide nanotubes (SWSiCNTs) were studied by first-principles simulations based on density functional theory within local spin density approximation. The band structures, density of states, and the influence of defects on the magnetism are studied for the Ag- and Au-doped SiC nanotubes. We obtained that the electronic properties of the SWSiCNTs are significantly changed by metal introduction and these systems show magnetic properties. While Ag- and Au-doped single-walled (6,0) SiC nanotube configurations, the width of the energy gaps of spin-up states decreases, and these systems show metallic character. The analysis of the partial density of states shows that the electronic states mainly come from the contribution of the p electrons of carbon and d electrons of transition metal atoms. The total energy calculations for Ag- and Au-doped SiC nanosystems show the stability of the antiferromagnetic phase. Our calculations show that SiC nanotubes doped with Ag and Au can be transformed into a new ferromagnetic material with half-magnetic character, and these nanomaterials are promising candidates for spintronics device applications.

This study investigated the possibility of extending the soot morphology analyses to acoustically agglomerated soot deposited on the surface of smoke alarms and of applying the validity of soot analysis for unique chemical signatures in the field of fire investigations. Through collecting soot samples, including agglomerated soot acquired from smoke alarms, this research presents a pioneering stride in soot morphology data analyses conducted by leveraging advanced deep learning methodologies. Preliminary outcomes underline that the proposed convolutional neural network model has the potential to decode intricate soot characteristics and to distinguish soot particle images between diverse fuel types and burning conditions. In particular, for the acoustically agglomerated soot collected by smoke alarms, it was also found possible to decode their intricate morphology by applying the proposed data-driven approach.

Colloidal particles fabricated using lithographic methods are used in micro-nanoengineering as well as biomechanical and chemical engineering. Much of the research in this field deals with close-packed colloidal particles in the form of continuous two-dimensional (2D) surface structures or membranes. The most common approach to modifying the arrangement and spacing of colloidal particles involves etching or the fabrication of micro-nanoimprinted structures at the micro- or nanoscale. In the current study, three-dimensional (3D) micro-printing was used to fabricate grid and honeycomb structures with precise control over the spatial distribution and height. We achieved a uniform distribution of polystyrene micro spheres across the surface of the structures by performing a variation of the floating assembly method referred to as drop deposition, which when implemented using methanol was shown to enhance the dispersal of microspheres in the mixture by reducing the London diverse force (LDF). The application of ultrasonic vibrations during microsphere deposition was shown to facilitate the integration of PS microspheres within the underlying lattice. We also found that methanol is highly effective in the removal of accumulated microspheres. The fabrication of grid and hexagonal structures spaced at intervals of 6, 6.5, and 7 μm followed by the deposition of PS microspheres (diameter = 6 μm) was shown to increase the water droplet contact angle from 103° (close-packed) to 110° (square arrangement) and 123° (hexagonal arrangement).